Exploring the Biocontrol Potential of Phanerochaete chrysosporium against Wheat Crown Rot.

The worldwide occurrence of wheat crown rot, predominantly caused by the pathogen Fusarium pseudograminearum, has a serious impact on wheat production. Numerous microorganisms have been employed as biocontrol agents, exhibiting effectiveness in addressing a wide array of plant pathogens through various pathways. The mycelium of the white-rot fungus Phanerochaete chrysosporium effectively inhibits the growth of F. pseudograminearum by tightly attaching to it and forming specialized penetrating structures. This process leads to the release of intracellular inclusions and the eventual disintegration of pathogen cells. Furthermore, volatile organic compounds and fermentation products produced by P. chrysosporium exhibit antifungal properties. A comprehensive understanding of the mechanisms and modalities of action will facilitate the advancement and implementation of this biocontrol fungus. In order to gain a deeper understanding of the mycoparasitic behavior of P. chrysosporium, transcriptome analyses were conducted to examine the interactions between P. chrysosporium and F. pseudograminearum at 36, 48, and 84 h. During mycoparasitism, the up-regulation of differentially expressed genes (DEGs) encoding fungal cell-wall-degrading enzymes (CWDEs), iron ion binding, and mycotoxins were mainly observed. Moreover, pot experiments revealed that P. chrysosporium not only promoted the growth and quality of wheat but also hindered the colonization of F. pseudograminearum in wheat seedlings. This led to a delay in the development of stem base rot, a reduction in disease severity and incidence, and the activation of the plant's self-defense mechanisms. Our study provides important insights into the biocontrol mechanisms employed by P. chrysosporium against wheat crown rot caused by F. pseudograminearum.

Metabolomics analysis of advancing humification mechanism in secondary fermentation of composting by fungal bioaugmentation.

The aim of this study was to investigate the differential metabolites and core metabolic pathways caused by fungal bioaugmentation (pH regulation and Phanerochaete chrysosporium inoculation) in secondary fermentation of composting, as well as their roles in advancing humification mechanism. Metabolomics analyses showed that inoculation strengthened the expression of carbohydrate, amino acid, and aromatic metabolites, and pH regulation resulted in the up-regulation of the phosphotransferase system and its downstream carbohydrate metabolic pathways, inhibiting Toluene degradation and driving biosynthesis of aromatic amino acids via the Shikimate pathway. Partial least squares path model suggested that lignocellulose degradation, precursors especially amino acids and their metabolism process enhanced by the regulation of pH and Phanerochaete were the main direct factors for humic acid formation in composting. This finding helps to understand the regulating mechanism of fungal bioaugmentation to improve the maturity of agricultural waste composting.

Effect of Phanerochaete chrysosporium induced phosphate precipitation on bacterial diversity during the soil remediation process.

Biomineralization by phosphate minerals and phosphate solubilizing fungi (PSF) has attracted great interest as a novel remediation method for heavy metal(loid) co-contaminated soil. It was very essential to investigate the microenvironment response with the application of amendments. In this study, three grain sizes of hydroxyapatites (HAP) and Phanerochaete chrysosporium (P. chrysosporium) were used to investigate the change in heavy metal(loid) fractions, soil physicochemical properties, and bacterial community during the remediation of Mangchang and Dabaoshan acidic mine soils. The results showed that the residual fractions in the two soils increased significantly after 35 days of remediation, especially that of As and Zn in Dabaoshan soils were presented at over 87%. In addition, soil pH, organic matter (OM), and available phosphorous (AP) were almost improved. 16S rRNA sequencing analysis indicated that the introduction of culture medium and P. chrysosporium alone changed bacterial abundance, but the addition of HAP changed the bacterial diversity and community composition by altering environmental conditions. The amendments in the research showed good performance on immobilizing heavy metal(loid)s and reducing their bioavailability. Moreover, the research suggested that environmental factors and soil inherent properties could influence the microbial community structure and composition.

Conversion of Corn Stover for Microbial Enzymes Production by Phanerochaete chrysosporium.

Phanerochaete chrysosporium, a white rot fungus, exhibits remarkable capabilities in producing various extracellular enzymes. These microbial enzymes find extensive applications in disrupting the intricate structure of plant cell walls, decolorizing synthetic dyes, and facilitating pulp extraction, among other functions. The process of solid-state fermentation stands out as an economical and sustainable approach, ideal for achieving high yields in enzyme production using lignocellulosic biomass as a substrate. In this research paper, both untreated and alkali pretreated corn stover materials served as substrates for enzyme production, leveraging the fungal strain's capacity to generate enzymes like cellulases and manganese peroxidase. The maximum production of endoglucanase was notably observed, reaching 121.21 ± 0.90 U/gds on the 9th day for untreated biomass and 79.75 ± 0.57 U/gds on the 6th day for treated biomass. Similarly, the peak exoglucanase production was recorded at 2.46 ± 0.008 FPU/ml on the 3rd day for untreated biomass and 0.92 ± 0.002 FPU/ml on the 6th day for treated biomass. Furthermore, the highest production of manganese peroxidase was achieved, with values of 5076.81 U/l on the 6th day for untreated biomass and 1127.58 ± 0.23 U/l on the 3rd day for treated biomass. These results collectively emphasize the potential of corn stover as a renewable and promising substrate for the production of essential enzymes.

Heterologously Expressed Cellobiose Dehydrogenase Acts as Efficient Electron-Donor of Lytic Polysaccharide Monooxygenase for Cellulose Degradation in Trichoderma reesei.

The conversion of lignocellulosic biomass to second-generation biofuels through enzymes is achieved at a high cost. Filamentous fungi through a combination of oxidative enzymes can easily disintegrate the glycosidic bonds of cellulose. The combination of cellobiose dehydrogenase (CDH) with lytic polysaccharide monooxygenases (LPMOs) enhances cellulose degradation in many folds. CDH increases cellulose deconstruction via coupling the oxidation of cellobiose to the reductive activation of LPMOs by catalyzing the addition of oxygen to C-H bonds of the glycosidic linkages. Fungal LPMOs show different regio-selectivity (C1 or C4) and result in oxidized products through modifications at reducing as well as nonreducing ends of the respective glucan chain. T. reesei LPMOs have shown great potential for oxidative cleavage of cellobiose at C1 and C4 glucan bonds, therefore, the incorporation of heterologous CDH further increases its potential for biofuel production for industrial purposes at a reduced cost. We introduced CDH of Phanerochaete chrysosporium (PcCDH) in Trichoderma reesei (which originally lacked CDH). We purified CDH through affinity chromatography and analyzed its enzymatic activity, electron-donating ability to LPMO, and the synergistic effect of LPMO and CDH on cellulose deconstruction. The optimum temperature of the recombinant PcCDH was found to be 45 °C and the optimum pH of PcCDH was observed as 4.5. PcCDH has high cello-oligosaccharide kcat, Km, and kcat/Km values. The synergistic effect of LPMO and cellulase significantly improved the degradation efficiency of phosphoric acid swollen cellulose (PASC) when CDH was used as the electron donor. We also found that LPMO undergoes auto-oxidative inactivation, and when PcCDH is used an electron donor has the function of a C1-type LPMO electron donor without additional substrate increments. This work provides novel insights into finding stable electron donors for LPMOs and paves the way forward in discovering efficient CDHs for enhanced cellulose degradation.

Removal of perfluorooctanoic acid (PFOA) in the liquid culture of Phanerochaete chrysosporium.

Perfluorooctanoic acid (PFOA) is becoming a concern due to its persistence, bioaccumulation, and potential harmful effects on humans and the environment. In this study, the fungus Phanerochaete chrysosporium (P. chrysosporium) was used to remove the PFOA in liquid culture system. The results showed that the average activities of laccase (Lac), lignin peroxidase (LiP), and manganese peroxidase (MnP) enzymes secreted by P. chrysosporium were 0.0003 U/mL, 0.013 U/mL, and 0.0059 U/mL, respectively, during the incubation times of 0-75 days. The pH of 3 and incubation time of 45-55 days were the optimum parameters for the three enzymes activities. The enzyme activities in P. chrysosporium incubation system were firstly inhibited by adding PFOA and then they were enhanced after 14 days. The maximum removal efficiency of PFOA (69.23%) was achieved after 35 days in P. chrysosporium incubation system with an initial PFOA concentration of 0.002 mM and no veratryl alcohol (VA). Adsorption was not a main pathway for PFOA removal and the PFOA adsorbed in fungi mycelial mat accounted for merely 1.91%. The possible products of PFOA contained partially fluorinated aldehyde, alcohol, and aromatic ring. These partially fluorinated compounds might result from PFOA degradation via a combination of cross-coupling and rearrangement of free radicals.

Effect of the inoculation of Phanerochaete chrysosporium on nitrogen migration and organic matter conversion during electrolytic manganese residue composting.

Composting has made it practicable to dispose electrolytic manganese residues (EMR) in a less toxic way, nevertheless, the decomposition and the loss of nitrogen is a critical issue. This study aimed to investigate the role of Phanerochaete chrysosporium (PC) inoculation on nitrogen migration and promotion of decomposing organic matter (OM), as well as the effect on bacterial community structure during EMR composting. The results exhibited that nitrogen loss tallied with the first-order kinetic model. PC inoculation increased the relative microbial abundance of Firmicutes, which improved the efficiency of nitrogen nitrification and OM degradation, and increased the germination index and total nitrogen content by 13.8% and 2.95 g/kg, respectively. Moreover, aromatic benzenes replaced heteropolysaccharides, alcohols and ethers as the main components of OM in fertilizer, leading up to a more stable humus structure. This study provides a rationale and a novel perspective on the resource and nutrient conservation of EMR-contaminated soils.

Synergistic lignin degradation between Phanerochaete chrysosporium and Fenton chemistry is mediated through iron cycling and ligninolytic enzyme induction.

Removal of recalcitrant lignin from wastewater remains a critical bottleneck in multiple aspects relating to microbial carbon cycling ranging from incomplete treatment of biosolids during wastewater treatment to limited conversion of biomass feedstock to biofuels. Based on previous studies showing that the white rot fungus Phanerochaete chrysosporium and Fenton chemistry synergistically degrade lignin, we sought to determine optimum levels of Fenton addition and the mechanisms underlying this synergy. We tested the extent of degradation of lignin under different ratios of Fenton reagents and found that relatively low levels of H2O2 and Fe(II) enhanced fungal lignin degradation, achieving 80.4 ± 1.61 % lignin degradation at 1.5 mM H2O2 and 0.3 mM Fe(II). Using a combination of whole-transcriptome sequencing and iron speciation assays, we determined that at these concentrations, Fenton chemistry induced the upregulation of 80 differentially expressed genes in P. ch including several oxidative enzymes. This study underlines the importance of non-canonical, auxiliary lignin-degrading pathways in the synergy between white rot fungi and Fenton chemistry in lignin degradation. We also found that, relative to the abiotic control, P. ch. increases the availability of Fe(II) for the production of hydroxyl radicals in the Fenton reaction by recycling Fe(III) (p < 0.001), decreasing the Fe(II) inputs necessary for lignin degradation via the Fenton reaction.

Regulating pH and Phanerochaete chrysosporium inoculation improved the humification and succession of fungal community at the cooling stage of composting.

This study aimed to explore the effect of regulating pH and Phanerochaete chrysosporium inoculation at the cooling stage of composting on the lignocellulose degradation, humification process and related precursors as well as fungal community for secondary fermentation. Results showed that composting with P. chrysosporium inoculation and pH regulation (T4) had 58% cellulose decomposition, 73% lignin degradation and improved enzyme activities for lignin decomposition. There was 81.98% increase of humic substance content and more transformation of polyphenols and amino acids in T4 compared to control. Inoculating P. chrysosporium affected the fungal community diversity, and regulating pH helped to increase the colonization of P. chrysosporium. Network analysis showed that the network complexity and synergy between microorganisms was improved in T4. Correlation and Random Forest analysis suggested that enriched Phanerochaete and Thermomyces in the mature stage of T4 were key taxa for lignocellulose degradation, and humic acid formation by accumulating precursors.

Effective bioremediation of clarithromycin and diclofenac in wastewater by microbes and Arundo donax L.

Bioremediation of pharmaceuticals has gained large research efforts, but there is still a need to improve the performance of bioremediation systems by selecting effective organisms. In this study, we characterized the capability to remove clarithromycin (CLA) and diclofenac (DCF) by the bacterium Streptomyces rochei, and the fungi Phanerochaete chrysosporium and Trametes versicolor. The macrolide antibiotic CLA and the non-steroid anti-inflammatory DCF were selected because these are two of the most frequently detected drugs in water bodies. Growth and content of the PhCs and a DCF metabolite (MET) by the energy crop Arundo donax L. were also evaluated under hydroponic conditions. The removal rate (RR) by S. rochei increased from 24 to 40% at 10 and 100 µg CLA L-1, respectively, averaged over incubation times. At 144 h, the RR by P. chrysosporium was 84%, while by T. versicolor was 70 and 45% at 10 and 100 CLA µg L-1. The RR by S. rochei did not exceed 30% at 1 mg DCF L-1 and reached 60% at 10 mg DCF L-1, whereas approached 95% and 63% by P. chrysosporium and T. versicolor, respectively, at both doses. Root biomass and length of A. donax were strongly affected at 100 µg CLA L-1. CLA concentration in roots and shoots increased with the increase of the dose and translocation factor (TF) was about 1. DCF severely affected both shoot fresh weight and root length at the highest dose and concentration in roots and shoots increased with the increase of the dose. DCF concentrations were 16-19 times higher in roots than in shoots, and TF was about 0.1. MET was detected only in roots and its proportion over the parent compound decreased with the increase of the DCF dose. This study highlights the potential contribution of A. donax and the tested microbial inoculants for improving the effectiveness of bioremediation systems for CLA and DCF removal.